Miter with Muscle

Do some splinin'

Splines add face-grain gluing surfaces as well as mechanical reinforcement to strengthen a mitered joint. Outside splines serve as decorative elements, too, especially if you use a contrasting wood species. The grain for inside or outside splines must run across the joint for maximum strength.

Outside splines
Add visible splines to a frame corner after assembling the joint and letting its glue cure. Cut the spline slots using a simple jig, like the one shown at right, with a tablesaw. Center the spline slots on the thickness of the frame, cutting them to a depth of about two-thirds of the frame-side width.